In a number of applications it is desirable to translate rotation of a first lever or shaft, about a pivot axis (e.g., planar rotation about an axis transverse to a long axis of the first shaft), to an opposite rotation of a second lever or shaft, about the same pivot axis. In some applications, it may also be desirable to transmit an axial rotation of the first shaft, about its long axis, to an axial rotation of the second shaft, about its long axis. That is, some applications could benefit from reversal of planar rotation and transmission of axial rotation between two shafts. Such applications include, for example, car steering pumps, gas valves etc.
One application where reversal of planar rotation about a pivot axis and transmission of axial rotation between two shafts would be desirable is rowing a boat. Rowing a boat traditionally has the rower facing toward the stern (back) of the boat. This leaves the rower blind to oncoming obstacles and hazards such as logs, debris, bridge abutments, other watercraft, etc. Rowing forward has the obvious benefit of allowing the rower to see and avoid problems in his path.
Rowing has been made more efficient and row boats made more stable by feathering of the oars where the oars can singularly or together be axially rotated about their long axis. While the oar is in the water and propelling the boat (e.g., pull or power stroke) the oar blade is disposed below the surface of the water and kept close to vertical to the water surface to provide maximum resistance. When the oar is raised out of the water, after the power stroke, and swung forward, air resistance is reduced if the oar blade is rotated (i.e., feathered) to be more horizontal to the water surface. In this horizontal orientation, the feathered blade also can skip along the water surface if the oar is held a little lower than desired. Likewise, the feathered blade will also cut through any waves which are in its path instead of slapping into them. Just before starting the next power stroke the oar is rotated back to being perpendicular to the surface of the water.
In order to row a boat forward in a direction a rower is facing, an oar must be split at a normal pivot point (e.g., oar lock on a gunwale) and a reversing mechanism put in place to make the outer section of the oar (e.g., oar shaft), beyond the pivot point, rotate opposite from the inner handle section (e.g., handle shaft). A number of proposed solutions exist for such a reversing mechanism. However, such proposed solutions fail to address how to permit feathering of such split oars. The present disclosure is presented in view of this background.